Television picture tubes and particularly color television picture tubes which generally operate at high voltages, for example in the 15 KV to 30 KV range, commonly generate undesired large transient voltages, noise and corona within the tube. Such voltages must be controlled and dissipated in order to avoid conduction of these high voltages through the tube pins and tube socket contacts to other portions of the circuitry associated with the tube; otherwise, these large voltages may damage the tube, the tube terminals and may also couple to and damage the associated electronics.
Many structures have been constructed to provide protection against such large transient voltages and such structures have been utilized widely in the commercial products. Note for example, U.S. Pat. No. 3,636,412 to Simovits and Dumas, entitled "Tube Socket Assembly"; U.S. Pat. No. 3,733,522 to Simovits and Dumas, entitled "Arc-Over Protective Device"; and U.S. Pat. No. 3,767,951 to Dumas and Simovits, entitled "Electron Tube Socket", all of which patents are assigned to the same assignee as the present invention.
In order to dissipate the excessive voltages, cathode ray tube sockets are normally provided with some type of safety device in the form of a grounding apparatus. In the event that the pin is operating at an excessive potential, the grounding apparatus permits a spark to jump or arc from the pin contact to ground. The foregoing prevents damage due to excessive potential at the selected one of the pins by providing a non-destructive path to ground to thus eliminate the excessive over voltage.
Commonly, one or more of the terminal pins is connected to higher voltage potentials than the other pins. Accordingly, the spacing between the high voltage arcing terminal and the grounding plate are selected to be greater than the space between the arcing terminals of the remaining pins and the grounding plate so that a higher potential is necessary before a spark can bridge the gap between the high voltage arcing terminal and the grounding plate. However, if a spark jumps from the high voltage arcing terminals to the ground plate, the potential of the ground plate may rise so fast that it can be properly dissipated, thereby causing a second spark to jump from the ground plate back to one of the other pin terminals thus seriously damaging the tube or the associated circuit. Structures are thus provided for separately connecting the high voltage arcing terminals to one grounding plate and grounding the arcing terminals of the remaining pins to a separate grounding plate. The separate grounding plate tends to prevent the sparks from jumping from the high voltage pin to ground and then to the remaining pins.
The present invention further provides an improved tube socket assembly operating at high potentials including dielectric chambers wherein the high voltage pin arc-gap terminals are positioned. The high voltage arc chamber is separated and segregated from the remaining pin contacts and includes a pair of controlled, uniformly spaced, high voltage spark gaps comprising two pairs of spaced hemi-spherical electrodes positioned in spaced relation to each other. The arc chamber is constructed to include a corona disrupter for minimizing the effects of corona discharge, as will be explained.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings, wherein: